On coincidence of classes of functions defined by a generalised modulus of smoothness and the appropriate inverse theorem
Berisha, Faton M.
41A35 (Primary) 41A50, 42A16 (Secondary) | Mathematics - Functional Analysis
We give the theorem of coincidence of a class of functions defined by a generalised modulus of smoothness with a class of functions defined by the order of the best approximation by algebraic polynomials. We also prove the appropriate inverse theorem in approximation theory.